Nanogenerators are emerging devices that convert mechanical energy to electricity using piezoelectric nanomaterials. Recently, a new type of electricity-generating device called a triboelectric nanogenerator (TG) has been developed based on triboelectric and electrostatic effects. During the generating process, charge transfer occurs between two periodically contacting surfaces with various polarities of triboelectricity. Because of the superior mechanical and electromechanical properties of nanoscale structures, TGs are able to harvest energy from rotating friction, fluid or air flow, human activities, and even wearable clothing. To date, the output power of TGs has reached the milliwatt/cm−2 level, which is sufficient to power many small electronic devices such as light-emitting diodes (LEDs), temperature sensors, portable electronic devices, displacement sensors, and several chemical and solvent vapor detectors.
To enhance the triboelectric performance, work has been done in increasing the effective friction by creating nanopatterns or nanofeatures on the film surface or by making multiple scale porous voids inside of polydimethyl-siloxane (PDMS). Furthermore, another promising strategy to enhance the triboelectric performance is to employ various kinds of conductive nanoparticles or nanowires dispersed in dielectric PDMS. However, most TGs require sophisticated surface patterns and nanostructure designs to attain high performance. Also, due to the soft and ductile behavior of nanoparticles/nanowires, the performance of TGs decreases with use or when encountering a large applied pressure. Therefore, output power stability remains an elusive goal. Moreover, the fabrication of many TGs using fillers as dielectrics involves the consumption of precious materials, for example, gold (Au) nanoparticles and carbon nanotubes. To minimize the usage of these expensive materials, utilization of other types of alternative fillers for triboelectric nanogenerators is highly desirable.
Therefore, it is a primary object and feature of the present invention to provide a biorenewable cellulose composite structure-based triboelectric nanogenerator with stable power output performance and a method of using the same.
It is a further object and feature of the present invention to provide a biorenewable cellulose composite structure-based triboelectric nanogenerator with stable power output performance which is simple to operative and inexpensive to manufacture.
It is a still further object and feature of the present invention to provide a biorenewable cellulose composite structure-based triboelectric nanogenerator with stable power output performance that generates greater electrical power than current triboelectric nanogenerators.
In accordance with the present invention, a triboelectric generator is provided. The triboelectric generator includes a first electrode having an inner surface and an outer surface and a second electrode having an inner surface and an outer surface. A dielectric layer has a first surface and a second surface in engagement with the inner surface of the second electrode. The dielectric layer is impregnated with biorenewable fillers. Periodic engagement of the first surface of the dielectric layer with the inner surface of the first electrode generates an electrical output across the first and second electrodes.
The inner surface of the first electrode is directed towards the inner surface of the second electrode and the dielectric layer is fabricated from polydimethylsiloxane (PDMS). The biorenewable fillers are fabricated from cellulose nanocrystals. The cellulose nanocrystals are flakes which are uniformly distributed throughout the dielectric layer. The flakes are orientated generally parallel to the first surface of the dielectric layer.
It is contemplated for at least one of the first and second electrodes is moveable between a first position wherein the first surface of the dielectric layer is spaced from the inner surface of the first electrode and a second position wherein the first surface of the dielectric layer is in contact with the inner surface of the first electrode.
In accordance with a further aspect of the present invention, a triboelectric generator is provided. The triboelectric generator includes a first electrode having a generally flat surface and a second electrode having a generally flat surface. A dielectric layer positioned adjacent to the surface of the first electrode. The dielectric layer is impregnated with biorenewable fillers and includes an outer surface. The periodic compression of the dielectric layer between the first and second electrodes generates an electrical output across the first and second electrodes.
The surface of the first electrode, is directed towards the surface of the second electrode and the dielectric layer is fabricated from polydimethylsiloxane (PDMS). The biorenewable fillers are fabricated from cellulose nanocrystals. The cellulose nanocrystals are flakes. The flakes are uniformly distributed throughout the dielectric layer and orientated generally parallel to the outer surface of the dielectric layer. At least one of the first and second electrodes is moveable between a first position wherein the outer surface of the dielectric layer is spaced from the second electrode and a second position wherein the outer surface of the dielectric layer is compressed by the second electrode.
In accordance with a still further aspect of the present invention, a method of generating electrical power is provided. The method includes the steps of positioning first and second electrodes in spaced relationship to each other and compressing a dielectric layer impregnated with biorenewable fillers between the first and second electrodes to generate an electrical output across the first and second electrodes.
The dielectric layer is fabricated from polydimethylsiloxane (PDMS) and the biorenewable fillers are fabricated from cellulose nanocrystals. The cellulose nanocrystals are flakes and wherein the method contemplates the additional step of uniformly distributing the flakes throughout the dielectric layer. The flakes are orientated generally parallel to the outer surface of the dielectric layer. The step of compressing the dielectric layer may include the additional step of periodically moving at least one of the first and second electrodes between a first position wherein the dielectric layer is spaced from at least of one of the first and second electrodes and a second position wherein the dielectric layer is compressed between the first and second electrodes.